461 research outputs found

    Kinetic resolution of (R,S)-1,2-isopropylidene glycerol (solketal) ester derivatives by lipases

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    AbstractA study on the enantioselective hydrolysis of (R,S)-1,2-isopropylidene glycerol (4-hydroxymethyl-2,2-dimethyl-1,3-dioxolane, solketal) octanoate catalyzed by different lipases was carried out. Among them, Pseudomonas sp. lipase proved to be the most effective. It was shown that the ester bearing the longer octanoyl acyl chain is a more suitable substrate for this lipase compared to the acetate counterpart. By properly combining enzyme load, temperature and reaction time, either the (S)-alcohol or the remaining ester could be obtained in moderate to high selectivities. Ethyl acetate was found to be the best solvent for the kinetic resolutions effected by such lipase but our results show that toluene may prove useful

    Técnica de biópsia hepática em eqüino por laparoscopia Hepatic biopsy in horses by laparoscopy

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    Este trabalho experimental objetivou a avaliação do uso da laparoscopia para biópsia hepática em eqüino e o estudo das possíveis alterações clínicas e laboratoriais decorrentes de tal procedimento. Foram utilizados 10 animais, os quais foram submetidos a procedimento cirúrgico em posição quadrupedal, por abordagem pelo flanco direito, no 17º espaço intercostal, após jejum alimentar e hídrico de 36 e 18 horas respectivamente. A avaliação pós-operatória constou de exame físico diário e colheita de amostras de sangue seriadas. O procedimento possibilitou inspeção dos órgãos e estruturas anatômicas localizados dorsalmente à direita da cavidade abdominal, favorecendo a escolha do local de biópsia hepática. Não foram observadas alterações no exame físico dos animais. Os exames hematológicos e de função hepática não apresentaram alterações significativas. Concluiu-se que o emprego da laparoscopia para realização de biópsia hepática em eqüino é simples, eficaz e seguro.<br>The purpose of this research was to evaluate the use of laparoscopy in obtaining hepatic biopsy in horses and to determine a possible clinical and laboratorial changes related to the procedure. Ten animals were submitted to 36 hours of fastening and 18 hours of water deprivation and then operated in the standing position, through a right flank approach at the level of the 17th intercostal space. Post-operative evaluation consisted of daily physical examination and seriated blood sampling. The procedure allowed for wide visualization of the viscera and anatomical structures located on the right side of the abdominal cavity, favouring the choice of the spot for hepatic biopsy collection. No changes were noted in the physical state of the animals and alterations in hemogram and hepatic function tests were not statistically significant. It was concluded that laparoscopy is a simple, effective and safe technique for obtaining hepatic biopsy specimens in horses

    Preparation of core-shell polymer supports to immobilize lipase B from Candida antarctica: Effect of the support nature on catalytic properties

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    Core–shell supports have been prepared and utilized to immobilize lipase B from Candida antarctica. The hydrophobic nature of the supports permitted to immobilize the enzyme via interfacial activation at low ionic strength. Different supports were prepared having different hydrophobicity and crosslinking degree, and compared to the commercially available. Accurel MP 1000 (hydrophobic macroporous polymer of propylene) is a commercial support described as advantageous in different circumstances and it was used as comparative control in the process of immobilization. The immobilized lipase preparations were evaluated in the hydrolysis of p-nitro-phenyl laurate and the esterification of oleic acid with ethanol. On the kinetic resolution of (±)-1,2-O-isopropylidene-3,6-di-O-benzyl-myo-inositol, vinyl acetate was used as activated acyl donor. Results were very diverse, as the lipase properties may be easily tuned via immobilization, and some of the supports permitted to obtain activities even a two fold factor higher than the same amount of lipase immobilized in Accurel MP 1000. Moreover, in many instances, the loading of the support with enzyme produced reduced total activity in some reactions while not in other. This was explained by changes in the physical properties of the support surface that may alter the entry of substrates. Supports PS-co-DVB/PS-co-DVB 25% and PMMA-co-DVB/PMMA-co-DVB 25% presented very good features to immobilize CALB.This work was supported by grants from Petrobras, CNPq and CTQ2009-07568 from Spanish Ministerio de Ciencia e Innovación.Peer Reviewe

    Preparation of core-shell polymer supports to immobilize lipase B from Candida antarctica: Effect of the support nature on catalytic properties

    No full text
    Core–shell supports have been prepared and utilized to immobilize lipase B from Candida antarctica. The hydrophobic nature of the supports permitted to immobilize the enzyme via interfacial activation at low ionic strength. Different supports were prepared having different hydrophobicity and crosslinking degree, and compared to the commercially available. Accurel MP 1000 (hydrophobic macroporous polymer of propylene) is a commercial support described as advantageous in different circumstances and it was used as comparative control in the process of immobilization. The immobilized lipase preparations were evaluated in the hydrolysis of p-nitro-phenyl laurate and the esterification of oleic acid with ethanol. On the kinetic resolution of (±)-1,2-O-isopropylidene-3,6-di-O-benzyl-myo-inositol, vinyl acetate was used as activated acyl donor. Results were very diverse, as the lipase properties may be easily tuned via immobilization, and some of the supports permitted to obtain activities even a two fold factor higher than the same amount of lipase immobilized in Accurel MP 1000. Moreover, in many instances, the loading of the support with enzyme produced reduced total activity in some reactions while not in other. This was explained by changes in the physical properties of the support surface that may alter the entry of substrates. Supports PS-co-DVB/PS-co-DVB 25% and PMMA-co-DVB/PMMA-co-DVB 25% presented very good features to immobilize CALB.This work was supported by grants from Petrobras, CNPq and CTQ2009-07568 from Spanish Ministerio de Ciencia e Innovación.Peer Reviewe

    Cultivo in vitro de embriões zigóticos e aclimatação de plântulas de coqueiro-anão In vitro culture of zygotic embryos and acclimatization of green dwarf coconut palm

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    O objetivo deste trabalho foi ajustar os protocolos de cultivo in vitro de embriões zigóticos e de aclimatação de plântulas de coqueiro-anão-verde do Brasil de Jiqui (Cocos nucifera L.). Os embriões zigóticos maduros, colocados assepticamente em meio de cultura líquido Y3 suplementado com 27,8 mg L-1 de Fe2SO4.7H2O e 60 g L-1 de sacarose, apresentaram maior germinação e formação de plântulas normais. As plântulas transferidas para meio indutor de enraizamento Y3, gelificado e suplementado com 1 mg L-1 de ANA, 0,5 mg L-1 de BAP e 2,5 g L-1 de carvão ativado, apresentaram incremento do desenvolvimento radicular e da parte aérea. Na fase de aclimatação, o substrato composto por areia lavada e pó de casca de coco seco, na proporção de 1:1, proporcionou maior sobrevivência das plântulas (58,33%), maior crescimento da parte aérea (39,08 cm) e maior número de folhas (6,33). Os protocolos estabelecidos para o cultivo in vitro de embriões zigóticos e a aclimatação de coqueiro-anão-verde de Jiqui podem ser utilizados no intercâmbio e conservação de germoplasma.<br>The objective of this work was to improve the protocols for culture and acclimatization of green dwarf coconut palm (Cocos nucifera L.). Mature zygotic embryos, cultivated in vitro aseptically in Y3 liquid medium culture, supplemented with 27.8 mg L-1 of Fe2SO4.7H2O and 60 g L-1 of sucrose, presented higher germination and normal plantlets formation. The plantlets transferred to Y3 semi-solid medium culture supplemented with 1 mg L-1 of ANA, 0.5 mg L-1 of BAP and 2.5 g L-1 of activated charcoal, promoted better root and shoot development. In the acclimatization phase, the 1:1 substrate composed of washed sand and coconut coir dust provided higher survival of plantlets (58.33%), larger growth of the aerial part (39.08 cm) and larger number of leaves (6.33). The established protocols for in vitro culture of zygotic embryos and acclimatization of green dwarf coconut palm plantlets can be applied to germplasm exchange and conservation

    Guarana (Paullinia cupana var. sorbilis), an anciently consumed stimulant from the Amazon rain forest: The seeded-fruit transcriptome

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    Guarana (Paullinia cupana var. sorbilis) is a plant native to the central Amazon basin. Roasted seed extracts have been used as medicinal beverages since pre-Colombian times, due to their reputation as stimulants, aphrodisiacs, tonics, as well as protectors of the gastrointestinal tract. Guarana plants are commercially cultivated exclusively in Brazil to supply the national carbonated soft-drink industry and natural product stores around the world. In this report, we describe and discuss the annotation of 15,387 ESTs from guarana seeded-fruits, highlighting sequences from the flavonoid and purine alkaloid pathways, and those related to biotic stress avoidance. This is the largest set of sequences registered for the Sapindaceae family. © 2007 Springer-Verlag

    Brazilian Flora 2020: Leveraging the power of a collaborative scientific network

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    International audienceThe shortage of reliable primary taxonomic data limits the description of biological taxa and the understanding of biodiversity patterns and processes, complicating biogeographical, ecological, and evolutionary studies. This deficit creates a significant taxonomic impediment to biodiversity research and conservation planning. The taxonomic impediment and the biodiversity crisis are widely recognized, highlighting the urgent need for reliable taxonomic data. Over the past decade, numerous countries worldwide have devoted considerable effort to Target 1 of the Global Strategy for Plant Conservation (GSPC), which called for the preparation of a working list of all known plant species by 2010 and an online world Flora by 2020. Brazil is a megadiverse country, home to more of the world's known plant species than any other country. Despite that, Flora Brasiliensis, concluded in 1906, was the last comprehensive treatment of the Brazilian flora. The lack of accurate estimates of the number of species of algae, fungi, and plants occurring in Brazil contributes to the prevailing taxonomic impediment and delays progress towards the GSPC targets. Over the past 12 years, a legion of taxonomists motivated to meet Target 1 of the GSPC, worked together to gather and integrate knowledge on the algal, plant, and fungal diversity of Brazil. Overall, a team of about 980 taxonomists joined efforts in a highly collaborative project that used cybertaxonomy to prepare an updated Flora of Brazil, showing the power of scientific collaboration to reach ambitious goals. This paper presents an overview of the Brazilian Flora 2020 and provides taxonomic and spatial updates on the algae, fungi, and plants found in one of the world's most biodiverse countries. We further identify collection gaps and summarize future goals that extend beyond 2020. Our results show that Brazil is home to 46,975 native species of algae, fungi, and plants, of which 19,669 are endemic to the country. The data compiled to date suggests that the Atlantic Rainforest might be the most diverse Brazilian domain for all plant groups except gymnosperms, which are most diverse in the Amazon. However, scientific knowledge of Brazilian diversity is still unequally distributed, with the Atlantic Rainforest and the Cerrado being the most intensively sampled and studied biomes in the country. In times of “scientific reductionism”, with botanical and mycological sciences suffering pervasive depreciation in recent decades, the first online Flora of Brazil 2020 significantly enhanced the quality and quantity of taxonomic data available for algae, fungi, and plants from Brazil. This project also made all the information freely available online, providing a firm foundation for future research and for the management, conservation, and sustainable use of the Brazilian funga and flora

    Development of the CMS detector for the CERN LHC Run 3

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    International audienceSince the initial data taking of the CERN LHC, the CMS experiment has undergone substantial upgrades and improvements. This paper discusses the CMS detector as it is configured for the third data-taking period of the CERN LHC, Run 3, which started in 2022. The entire silicon pixel tracking detector was replaced. A new powering system for the superconducting solenoid was installed. The electronics of the hadron calorimeter was upgraded. All the muon electronic systems were upgraded, and new muon detector stations were added, including a gas electron multiplier detector. The precision proton spectrometer was upgraded. The dedicated luminosity detectors and the beam loss monitor were refurbished. Substantial improvements to the trigger, data acquisition, software, and computing systems were also implemented, including a new hybrid CPU/GPU farm for the high-level trigger

    Development of the CMS detector for the CERN LHC Run 3

    No full text
    International audienceSince the initial data taking of the CERN LHC, the CMS experiment has undergone substantial upgrades and improvements. This paper discusses the CMS detector as it is configured for the third data-taking period of the CERN LHC, Run 3, which started in 2022. The entire silicon pixel tracking detector was replaced. A new powering system for the superconducting solenoid was installed. The electronics of the hadron calorimeter was upgraded. All the muon electronic systems were upgraded, and new muon detector stations were added, including a gas electron multiplier detector. The precision proton spectrometer was upgraded. The dedicated luminosity detectors and the beam loss monitor were refurbished. Substantial improvements to the trigger, data acquisition, software, and computing systems were also implemented, including a new hybrid CPU/GPU farm for the high-level trigger
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